Buckle



FIG. 1 is a perspective view of a buckle;

FIG. 2 is a front view of the buckle;

FIG. 3 is a rear view of the buckle;

FIG. 4 is a right-side view of the buckle;

FIG. 5 is a left-side view of the buckle;

FIG. 6 is a top view of the buckle; and,

FIG. 7 is a bottom view of the buckle.

The broken lines form no part of the claimed design. 

The ornamental design for a buckle, as shown and described. 